1. Field of the Invention
The present invention relates to a coupling for tubes for carrying a fluid.
The present invention can be, for example, used as a coupling for tubes for a refrigerant in a refrigerating circuit.
2. Description of Related Art
A connection, for tubes for passage of a fluid, by means of a nut union is known as a prior art. The cost for producing this type of the coupling is low. However, the adjustment of tightening the nut, which is time consuming, is essential during assembly. From the total view point, the cost of this type is high. Furthermore, during the use of the nut union, a tool, such as a torque wrench, is necessary in order to tighten the nut. As a result, a space is necessary around the coupling to allow the tool to be used.
In view of the above, an improvement in the coupling, which can eliminate the tool for tightening and can reduce the working time, was proposed in, for example, Japanese Examined Patent Publication No. 60-59478, wherein a circular spring for holding the outside of the female coupling was proposed.
However, in the construction in Japanese Examined Patent Publication No. 60-59478, a special tool is required to separate the male and female couplings. In other words, an operator who comes to a site without having the special tool cannot dismantle the coupling.